Remove rpc error when shut down daemon

RPC connection closing error will be reported every time we shutdown
daemon, this error is expected, so we should remove this error to avoid
confusion to user.

Signed-off-by: Zhang Wei <zhangwei555@huawei.com>

libcontainerd/remote_linux.go

@@ -23,6 +23,7 @@ import (
 	"golang.org/x/net/context"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/transport"
 )
 
 const (
@@ -37,17 +38,18 @@ const (
 
 type remote struct {
 	sync.RWMutex
-	apiClient   containerd.APIClient
-	daemonPid   int
-	stateDir    string
-	rpcAddr     string
-	startDaemon bool
-	debugLog    bool
-	rpcConn     *grpc.ClientConn
-	clients     []*client
-	eventTsPath string
-	pastEvents  map[string]*containerd.Event
-	runtimeArgs []string
+	apiClient     containerd.APIClient
+	daemonPid     int
+	stateDir      string
+	rpcAddr       string
+	startDaemon   bool
+	closeManually bool
+	debugLog      bool
+	rpcConn       *grpc.ClientConn
+	clients       []*client
+	eventTsPath   string
+	pastEvents    map[string]*containerd.Event
+	runtimeArgs   []string
 }
 
 // New creates a fresh instance of libcontainerd remote.
@@ -147,6 +149,7 @@ func (r *remote) Cleanup() {
 	if r.daemonPid == -1 {
 		return
 	}
+	r.closeManually = true
 	r.rpcConn.Close()
 	// Ask the daemon to quit
 	syscall.Kill(r.daemonPid, syscall.SIGTERM)
@@ -254,6 +257,11 @@ func (r *remote) handleEventStream(events containerd.API_EventsClient) {
 	for {
 		e, err := events.Recv()
 		if err != nil {
+			if grpc.ErrorDesc(err) == transport.ErrConnClosing.Desc &&
+				r.closeManually {
+				// ignore error if grpc remote connection is closed manually
+				return
+			}
 			logrus.Errorf("failed to receive event from containerd: %v", err)
 			go r.startEventsMonitor()
 			return